1. Technical Field of the Invention
The present invention relates to a subscriber feature within a telecommunications network, and in particular, to the provision of an enhanced do not disturb (DND) subscriber feature within such a network.
2. Description of Related Art
With developments and improvements in telecommunications networks, originating subscribers and terminating subscribers are able to instruct serving telecommunications networks or exchanges to provide user-specific subscriber features. Such a feature includes a do not disturb (DND) subscriber feature. By activating the DND subscriber feature, the associated telecommunications subscriber is able to block or deny incoming call connections. Furthermore, in order to selectively deny or block incoming call connections, the subscriber may further store a plurality of allowed and/or disallowed directory numbers within the serving telecommunications exchange. In response to a request for an incoming call connection, the serving telecommunications exchange then compares the calling party directory number (CgPn) associated with the received incoming call connection with the allowed and/or disallowed directory numbers and accordingly denies or effectuates the call connection.
Other terminating call treatments include call forwarding variable (CFV) where all or selected incoming calls are directly forwarded to a predefined forward-to-number; call forwarding busy (CFB) where all or selected incoming calls toward a busy called party subscriber are forwarded to a predefined forward-to-number; or anonymous call rejection (ACR) where an incoming call connection with a refusal to identify the associated calling party number to the called party subscriber is denied.
Reference is now made to FIG. 1 illustrating a telecommunications network 5 effectuating a call connection between a calling party subscriber and a called party subscriber in a conventional manner. The calling party subscriber 10 originates a call connection towards the called party subscriber 20 by dialing a directory number associated with the called party subscriber 20 (hereinafter referred to as a called party directory number--CdPn). An originating telecommunications exchange 30 detects the calling party subscriber's instructions, and transmits a call setup signal 40 towards a terminating telecommunications exchange 50 associated with the called party subscriber 20. Such a call setup signal may comprise an Integrated Service Digital Network User Part (ISUP) based signal, such as an Initial Address Message (IAM). The transmitted IAM signal 40 includes a calling party directory number (CgPn) representing the originating subscriber 10, a called party directory number (CdPn) representing the terminating subscriber 20, and a parameter specifying the calling party subscriber's private indicator. Such a private indicator instructs the terminating telecommunications exchange to display or not to display the associated calling party directory number to the terminating subscriber. As an illustration, in case the private indicator is set, a "Not Available" message is displayed on a Customer Premise Equipment (CPE, also known as a caller id display unit) attached to the called party subscriber terminal.
After receiving the incoming call connection request, the terminating telecommunications exchange 50 determines whether any one of the above described terminating subscriber features is currently activated for the called party subscriber. For example, the terminating telecommunications exchange 50 ascertains that the DND subscriber feature is currently activated for the called party subscriber 20. In case of a universal DND subscriber feature, an associated DND application module 60 rejects the incoming call connection by either generating a congestion / busy tone towards the calling party subscriber or by playing an announcement message thereto. In case of a selective DND subscriber feature, the DND application module 60 compares the calling party directory number (CgPn) included within the received IAM signal 40 with the allowed and/or disallowed directory numbers stored at a register 70 to determine whether to allow or deny the received incoming call connection.
Furthermore, in order to enable a calling party subscriber to override or by-pass the above described terminating call treatment subscriber features, a number of additional subscriber features or functions are also available. For example, a particular subscriber defines a service code or access code within the serving telecommunications exchange. A calling party subscriber may then override the activated terminating call treatment or call barring subscriber feature by providing the necessary service code or access code and establish a call connection with the otherwise restricted called party subscriber. As an illustration, in case the calling party subscriber's incoming call connection request is initially denied by the DND application module associated with the terminating exchange, the terminating exchange may further instruct the calling party subscriber to provide the necessary access code. Upon entering the requested access code via DTMF, for example, the terminating exchange then overrides the terminating call treatment and effectuates a call connection therebetween.
However, such a solution requires the subscriber to inconveniently communicate such an access code to all of his or her friends, associates, and the like. Furthermore, in case a person without access to the access code desires to urgently establish a call connection with the called party subscriber, the above mechanism provides no solution.
Accordingly, there is a need for a mechanism to enable a calling party subscriber to override an existing terminating call treatment subscriber feature without providing additional called party subscriber associated data or information to a terminating telecommunications exchange serving the called party subscriber.